Modularly constructing a software defined radio

ABSTRACT

Systems and methods are provided for modularly constructing a software defined radio (“SDR”). Given an SDR kernel (i.e., a potentially platform-neutral definition of digital signal processing functionality and control operations necessary to implement the core portion of a software defined radio implementing a particular radio standard), an optional description of governmental regulations for a particular locality, and an interface harness providing the necessary components for interfacing to specific communication channels and devices (including SDR hardware components), an SDR factory component performs a process of constructing an SDR software component for implementing a particular radio standard on a particular host. The SDR software component may additionally construct components which restrict the operation of the resulting SDR software component. The SDR kernel may be protected by one or more digital rights management (“DRM”) policies which may be enforced both at the time the SDR software component is constructed and while it is operating.

BACKGROUND

The terms software defined radio (“SDR”) and software radio (“SR”) applybroadly to the technique of using software to define and implementportions of a radio system that would previously have been implementedusing custom-built hardware. The power of general-purpose processors andsoftware configurable hardware has steadily risen to a level where theycan perform many of the computationally intensive digital signalprocessing (“DSP”) functions performed by radio systems and SDRcapitalizes on this increase in power. The SDR software component istypically a hardware device (e.g., a field programmable gate array)which has been configured by software, or a program executing on ageneral-purpose computer. This SDR software component typicallyinterfaces, via data communication channels, to an SDR hardwarecomponent providing the functionality necessary to support SDR tasksthat cannot be accomplished by the reconfigurable hardware module orgeneral-purpose computer being used (e.g., the analog transmission andreception of radio signals and analog filtering of the received analogsignals).

In modem SDR systems, the SDR hardware component typically provideslittle of the total SDR functionality as most of the DSP work canpresently be done using software. SDR allows the functionality definedby software to be redefined without requiring the replacement ofhardware components. Instead, only the software that defines thesefunctional modules is replaced. The more functionality that is definedby software, the more flexible and reconfigurable the resulting SDRbecomes. The combination of the SDR hardware component and SDR softwarecomponent can be used to support a variety of radio standards by runninga different SDR software component for each implementing standard.

As a result of the complexity and various nuances of the great manyradio standards that exist, the SDR software components implementingthese radio standards may be provided by an equally large variety ofthird party providers. Despite their relative simplicity, a great numberand variety of SDR hardware components with varying capabilities arealso available. Each SDR software component must be equipped tointerface with an SDR hardware component as well as with clientapplications which make use of the SDR to send or receive data.Supporting each of the methods for a client application to connect tothe SDR software component, and the many available SDR hardwarecomponents quickly becomes a daunting task for those providing the SDRsoftware components, distracting them from their core area of concernand competency. Furthermore, a majority of the effort necessary toprovide such support is repeated by each of the providers of SDRsoftware components. These factors currently limit the universality andpracticality of SDR systems.

SUMMARY

The Inventors have identified a need for modularly constructing an SDRand herein disclose an invention for doing so. One aspect of the presentinvention of modularly constructing an SDR provides an abstraction ofthe definition of the software defined signal processing components ofthe SDR (herein referred to as the SDR kernel) from all other componentsof the SDR, such as the platform-specific and protocol-dependentinput/output interface components (e.g., a component for interfacing toUSB on an ×86 general-purpose computer running the Microsoft® Windows®operating system) as well as from particular SDR hardware components.The aforementioned aspect of modularly constructing an SDR implicitlyprovides support for the establishment of a simple interface definitionbetween an SDR kernel and the rest of the SDR. Thus, developers of SDRkernels can focus attention away from supporting the plethora ofprotocol/hardware platform/operating system/SDR hardware componentcombinations toward developing SDR kernels for the many radio standardsthat exist and the many more that are likely to emerge.

Modularly constructing an SDR empowers a system to utilize the SDRkernels provided by a variety of publishers to effectively become auniversal communication device. The process of supporting a radiostandard is thus reduced to one of obtaining an SDR kernel describing anSDR kernel component for implementing the radio standard, andconstructing an SDR software component for executing the SDR kernelcomponent on a particular system. As disclosed herein, SDR kernels maybe obtained in a variety of ways and, in one aspect of the invention, anSDR kernel is attained by download from an internet-based service.

In another aspect of modularly constructing an SDR, regulation datacomprising government regulations for one or more localities is used toprevent the construction of an SDR which would violate the regulationsdescribed by the regulation data. In another aspect of the invention,the SDR software component is constructed with a regulation componentfor ensuring that, while the SDR is executing, no control data is sentfrom the SDR software component to the SDR hardware component whichcould lead to the SDR violating regulations described by the regulationdata. The aspects of the present invention utilizing the regulation datahelp ensure that a modularly constructed SDR behaves as a “goodcitizen.”

BRIEF DESCRIPTION OF THE DRAWINGS

It is noted that components that appear in multiple figures and functionidentically are given the same labels in each of the figures.

FIG. 1 is a block diagram of an SDR system as known in the prior art.

FIG. 2 is a block diagram illustrating an example of a system accordingto some aspects of the present invention.

FIG. 3 is a flow diagram for an example of a process for constructing anSDR software component.

FIG. 4 is a block diagram showing more detail pertaining to theconstruction of an SDR software component.

FIG. 5 is a block diagram illustrating an example of a system accordingto some aspects of the present invention.

FIG. 6 is a flow diagram of an example routine for sending an SDR kernelto a client system.

DETAILED DESCRIPTION

Before discussing the present invention, we first explore an embodimentof a typical SDR system as known in the prior art.

FIG. 1 is a block diagram showing a typical SDR system as known in theprior art. An SDR software component 10, running on a host (e.g.,general-purpose computer or software-configured hardware), is connectedto an SDR hardware component 20 by one or more data channels permittingthe transmission of: digital baseband output data from the SDR softwarecomponent 10 to the SDR hardware component 20, digital baseband inputdata from the SDR hardware component 20 to the SDR software component10, and control data from the SDR software component 10 to the SDRhardware component 20. The SDR software component 10 receives clientinput data from an SDR client 15 and sends client output data to the SDRclient 15.

The digital baseband output typically results from the SDR softwarecomponent 10 performing a series of DSP functions necessary to preparethe client input data from the SDR client 15 for transmission by the SDRhardware component 20. These functions may include: source encoding,encryption, error-correction coding, and baseband modulation. Thisdigital baseband output must be converted to analog form before beingtransmitted. This is accomplished through the use of a digital-to-analogconverter (“DAC”) 22. Once converted, the analog baseband output is sentto the basic radio transceiver 26 for further processing, which mayinclude upconverting the baseband signal to the appropriate transmissionfrequency and amplification. After being appropriately processed, thesignal is sent to an antenna 30 for transmission.

Signals received by the antenna 30 are processed by the basic radiotransceiver 26, where they may be filtered to obtain a desired frequencyrange, downconverted to the appropriate baseband frequency modulation,and sent to an analog-to-digital converter (“ADC”) 24 to be convertedfrom analog baseband data to digital baseband data. This digitalbaseband data is then sent to the SDR software component 10 where aseries of DSP functions are performed which may include: basebanddemodulation, error correction, decryption, and source decoding. Theresulting data stream may then be sent as client output data to the SDRclient 15.

The control data sent from the SDR software component 10 to the SDRhardware component 20 permits the SDR software component 10 to sendcommands to the SDR hardware component 20. These commands may be used toadjust important parameters such as the center frequency and bandwidthof interest and may define a frequency range to which the basic radiotransceiver 20 can tune. Additional commands may influence, for example,how the incoming signal is filtered as well as invoke basic actions suchas powering down the SDR hardware component 20.

The digital baseband input, digital baseband output, control data,client input, and client output usually are transmitted across a datachannel which makes use of specialized hardware and transmissionprotocols (e.g., USB, PCI, an SCSI). Thus, the SDR software component 10must implicitly have the ability to interface with these channels andany software components supporting them.

FIG. 2 is a block diagram illustrating an example of a system accordingto some aspects of the present invention. This system supports themodular construction of an SDR software component given various data.The SDR hardware component 60 is configured in the same manner as theSDR hardware component 20 which was disclosed earlier, with theexception of having the additional ability to send specificationsdetailing its capabilities. The sending of these specifications mayoccur in a variety of ways such as: when the SDR hardware component 60is powered-up, periodically, or as a result of control data forrequesting the specifications to be sent. An SDR factory component 45reads an SDR kernel 50, an interface harness 53, and optionally inputsregulation data 55 and may be, for example, be implemented as hardwareor as a program running on a general-purpose computer. The DRM component43, when present, provides enforcement of DRM policies which may bepresent in the SDR kernel 50 and may decrypt some or all of the contentsof the SDR kernel 50 before sending it to the SDR factory component 45to be read.

The SDR kernel 50 comprises the definition of the configuration andarrangement of components such as signal processing elements and controlelements. The SDR kernel also provides a simple interface definitionwhich may, for example, specify connections for SDR client input, SDRclient output, SDR hardware component input, SDR hardware componentoutput, and control data output. The simple interface need not provide adefinition of components for communicating over particular data channels(e.g., USB, PCI, SCSI, Serial, Parallel, and Ethernet) which appear in atypical host. The SDR kernel 50 may be provided as software (e.g.,object code, source code) or non-software (e.g., XML, unstructured textdata, binary data) and may further comprise tamper-resistant data suchas: a digitally signed checksum of the data in the SDR kernel 50 (forensuring the contents have not been corrupted or altered), a digitalsignature from the publisher, and digitally signed testing certificationwith a checksum of the data in the SDR kernel (for ensuring the contentshave been deemed safe by a trusted party). While digital signatures aregiven as an example of a tamper-resistant technology for securing thisdata, it us understood that any technology providing a similar functionis also applicable to this aspect of the invention. As previouslydisclosed, the SDR kernel 50 may be protected by DRM for enforcing usagepolicies set by its publisher. If the SDR kernel 50 does not compriseobject code, it can be converted by the SDR factory component 45 to anSDR kernel component comprising a series of instructions suitable forconfiguring a host to implement the defined radio standard.

The interface harness 53 comprises all necessary software components forinterfacing an SDR kernel component (i.e., the platform-specificinstructions implementing a radio standard constructed from an SDRkernel 50) to an SDR client 15 and an SDR hardware component 60. Byusing a separate interface harness 53, the SDR kernel 50 need onlyimplement a single (possibly host-independent) interface.

The regulation data 55 comprises regulatory information such as thelicensed and unlicensed frequency bands and transmission power limitsfor certain frequency bands for one or more localities. The regulationdata 55, when present, may be used by the SDR factory component 40 in atleast two ways, the ways being usable together or separately.

One way of using the regulation data 55 is to prevent the constructionof an SDR software component which would violate the regulationsdescribed within the regulation data 55 and is only applicable when theoperating specifications (e.g., bandwidth, frequencies used, signalpower) of the SDR kernel 50 can be determined. Determining thesespecifications can be done easily when they are explicitly providedwithin the SDR kernel 50. If the specifications are not explicitlyprovided, it may be possible to determine these specifications byanalyzing the description in the SDR kernel 50. Once the specificationsare determined, a comparison with the regulation data 55 can beperformed to determine if any violations might occur. If so, an errorcan be raised and the construction of the SDR software component 40halted.

Another way to use the regulation data 55 is to construct a regulationcomponent as part of the constructed SDR software component 40. Thisregulation component censures the control data sent to the SDR hardwarecomponent 60 to ensure that the resulting settings in the SDR hardwarecomponent 60 will not violate any regulations. It is also possible toraise a warning when the control data instructs the SDR hardwarecomponent 60 to configure itself in a way such that it would violate anyregulations without stopping the control data from being sent.

The SDR kernel 50, interface harness 53, and regulation data 55 may eachbe stored on any computer-readable medium (e.g., CD, DVD, hard disk,flash storage, RAM), and may also be transmitted across any datacommunication network (e.g., internet, LAN) using any appropriateprotocol (e.g., HTTP, TCP/IP, FTP, SOAP). The SDR kernel 50 and theregulation data 55 may also be combined to form a single file or storedseparately.

The SDR factory component 45 uses the definition provided by the SDRkernel 50 along with any provided regulation data 55 to construct andoptionally execute an SDR software component 40. If the SDR kernel 50 isprotected by DRM policies, the SDR factory component 45 may itselfenforce the DRM policies or read the SDR kernel 50 through a DRMcomponent 43 which enforces the policies. The DRM policies may beenforced at the time the SDR factory component 45 is being constructedand the SDR software component 40 and may additionally construct asub-component of the SDR software component 40 to enforce DRM policiesduring the execution of the SDR software component 40. In most cases, anSDR kernel 50 that is protected by DRM policies will have contents thatare unreadable by the SDR factory component 45. Making the contents ofthe SDR kernel 50 unreadable may be accomplished, for example, by usingencryption to scramble the contents. The encrypted portions of the SDRkernel 50 must therefore be unencrypted before the SDR softwarecomponent 40 construction process can continue. This decryption can beperformed either by the DRM system 43 through which the SDR factorycomponent 45 may read the SDR kernel 50, or by the SDR factory component45 itself.

Though it has been indicated that the SDR factory component 45constructs a separate SDR software component 40, we recognized that theSDR factory component 45 could alternatively transform at least part ofitself into the SDR software component rather than constructing aseparate SDR software component 40.

Once the SDR software component 40 is executing on the host, the SDRclient 15 and the SDR hardware component 60 may begin communicating withit. We note that the SDR client 15 may comprise one or more hardware andsoftware components and may communicate with the SDR software component40 via any communications means including but not limited to: conductivewires, optical fibers, network interface cards, serial ports, PS2 ports,parallel ports, USB ports, the PCI bus, and SCSI channels. The digitalbaseband output, digital baseband input, and control data may betransmitted using any interface method suitable for interfacing with thehost executing the SDR software component 40 and need not all use thesame method. When the host is a general-purpose computer, for example,these methods may include: USB, PCI, FIREWIRE, serial port, parallelport, network interface card, and SCSI. We note that only one of thedigital baseband input and digital baseband output are necessary tosupport a system which is useful for some applications. We further notethat when using high performance ADC 24 and DAC 22 components in the SDRhardware component 60, the baseband input and baseband output maycommunicate data that has a modulation which has not been downconverted.

The specifications data transferred from the SDR hardware component 60to the SDR software component 40 may comprise the operationallimitations of the SDR hardware component 60 (e.g., maximum allowablebandwidth and frequency). This information allows the SDR softwarecomponent 40 to determine if the SDR hardware component 60 can supportthe standard it embodies. The SDR hardware component 60 can alsooptionally be configured to return an error code to the SDR softwarecomponent 40 rather than providing specifications data. An example ofwhy an SDR hardware component 60 would be unable to support an SDRsoftware component 40 is that one or more of the frequencies it uses maylie outside the range of the basic radio transceiver 66. Another exampleis that the bandwidth needed may be too wide for the abilities of theADC 64 or DAC 62. If the SDR hardware component 60 cannot support theSDR software component 40, the SDR software component 40 can generate ameaningful error message and terminate.

When an SDR software component 40 is executing, it can communicatecontrol data to the SDR hardware component 60. This control data maycomprise commands to: power down the SDR hardware component 60, specifythe frequencies of interest and their corresponding bandwidths, and setfilter settings. These control commands allow the SDR software component40 to dynamically change the operating parameters of the SDR hardwarecomponent 60 and are important for supporting multiple radio standards.The exact set of control data that can be sent may depend upon theparticular SDR hardware component 60 being used.

The SDR kernel 50 also may comprise data specifying the minimum requiredspecifications required of an SDR hardware component 60 capable ofsupporting the radio standard described by the SDR kernel 50. The SDRfactory component 45 can access the specifications of the SDR hardwarecomponent 60 either directly from the SDR hardware component 60,operatively by reading the specifications from a computer-readablemedium on which they have been stored, or by any other means. The SDRfactory component 45 reviews the specifications of the SDR hardwarecomponent 60 to determine, before constructing the SDR softwarecomponent 40, if the SDR hardware component 60 can support the standarddescribed by the SDR kernel 50. If the SDR hardware component 60 isdetermined to be unable to support the standard, the SDR factorycomponent 45 terminates the construction of the SDR software component40 and optionally indicates an error. If the SDR factory component 45cannot determine the minimum required specifications from the SDR kernel50, the SDR factory component 45 may construct a specificationsenforcement component which reads the specifications data from the SDRhardware component 60 and censures outgoing control data to preventcommands from being sent to the SDR hardware component 60 which the SDRhardware component 60 could not support and may prevent equipment damagein some instances.

FIG. 3 is a flow diagram of an example of a process for constructing anSDR software component. In 301, either the DRM component 43 or the SDRfactory component 45 reads the contents of the SDR kernel 50. Aspreviously disclosed, the SDR kernel 50 may be read from anycomputer-readable medium including any data communication network.

In 302, either the DRM component 43 or the SDR factory component 45reads any DRM policies that are embedded within the SDR kernel 50 andchecks to see if the conditions of the policies are currently satisfied.These policies may include ensuring the SDR kernel 50 is being read on aparticular host and ensuring the current date-time is within a specificdate-time range. If it is determined in 302 that one or more DRMpolicies are not satisfied, an error is raised in 303 and theconstruction of the SDR software component is terminated. On the otherhand, if it is determined that the DRM policies are satisfied, the SDRkernel 50 is decrypted in 304, if necessary. This allows the remainingcontents of the SDR kernel 50 to be read and used in further along inthe SDR software component 40 construction process.

In 305, the SDR factory component 45 makes use of data stored within theSDR kernel 50 to determine if any changes have been made to the SDRkernel 50 since the contents were last verified by a publisher ortrusted third party. This act may, for example, be accomplished byreading data such as a digitally signed checksum from the contents ofthe SDR kernel 50, verifying the authenticity of the signature, and thenperforming a checksum calculation on the SDR kernel 50 to ensure thatthe two checksums match. A reason for performing this act is to ensurethat the contents of the SDR kernel 50 have not been corrupted by errorsin storage or transmission and to further ensure that a third party doesnot modify the SDR kernel 50 to perform in a manner the publisher didnot intend. If it is determined that the contents of the SDR kernel 50have been modified from their intended state, an error is raised in 306.After raising the error, the SDR factory component 45 terminates anddoes not construct an SDR software component from the SDR kernel 50.

If it is determined in 305 that the SDR kernel 50 has not been corruptedor modified, the SDR factory component 45 makes use of informationprovided within the SDR kernel 50 to identify the publisher of the SDRkernel 50. It can next be determined if the publisher is a trustedpublisher by, for example, checking the identity of the publisheragainst a list of trusted publishers. Alternatively, a chain of trustmay be determined to exist whereby the publisher is determined to betrustworthy in a less direct manner. When a publisher cannot be verifiedas trustworthy, it is not necessarily the case that the SDR kernel 50should not be used. In 308, after the SDR factory component 45 fails tofind the publisher trustworthy, the SDR factory component 45 raises awarning. This warning may comprise identification information for thepublisher (e.g., company name) and present a choice to either: 1)continue using the SDR kernel 50 even though the publisher is not deemedtrustworthy, or 2) abandon its use.

If it is determined in 307 that the publisher of the SDR kernel 50 istrustworthy, or if in 308 the decision is made to continue using the SDRkernel 50 even if the publisher is not determined to be trustworthy, theSDR factory component 45 next performs 309. In 309, the SDR factorycomponent 45 uses information from the SDR kernel 50 to check for anytesting certifications that may be present. These certifications may,for example, comprise a checksum of the data in the SDR kernel 50 and besigned by a certificate known to signify that the SDR kernel 50 haspassed a series of tests to ensure quality. If an SDR kernel 50 lacks adesired certification, the SDR factory component 45 raises a warning in310. The warning may comprise information about the desiredcertification that is missing and present a choice to either: 1)continue using the SDR kernel 50 even though the desired certificationis missing, or 2) abandon its use.

If it is determined in 309 that the SDR kernel 50 has all desiredcertifications, or if the decision is made in 310 to continue using theSDR kernel 50 even if the desired certifications are not present, theSDR factory component 45 next performs 311. In 311, the SDR factorycomponent 45 reads the specification data detailing the capabilities ofthe SDR hardware component 60. This may be accomplished, for example, byrequesting the data directly from the SDR hardware component 60, readinga file containing the information, or prompting for the information. Thespecification information for the SDR hardware component 60 may comprisedata outlining the ranges supported for each parameter relevant to theconfigurable operation of the SDR hardware component 60.

Once obtained, the specification data can be used in 312 to determine ifthe SDR hardware component 60 is capable of supporting the requirementsof the SDR kernel 50. If data is included in the SDR kernel 50indicating its operational ranges, a comparison can be made between thisdata and the specification data to determine if any of the ranges forthe SDR kernel 50 data lie beyond those of the capabilities of the SDRhardware component 60. If it is determined in 312 that the requirementsof the SDR kernel 50 are beyond than the abilities of the SDR hardwarecomponent 60 as given in the specification data, an error is raised in313 and the SDR factory component 45 terminates construction of the SDRcomponent. This act is useful because it prevents the construction of anSDR software component 40 that would attempt to drive an SDR hardwarecomponent 60 beyond its abilities. This helps reduce the possibility ofequipment damage and lessens the time spent debugging an SDR that is notworking properly as a result of an SDR hardware component 60 that cannotsupport a given SDR kernel 50.

If it is determined that the SDR hardware component 60 is capable ofsupporting the SDR kernel 50, then the SDR factory component 45 moves onto 314. In 314, the SDR factory component 45 reads the regulation data55. As previously disclosed, the regulation data 55 comprises datarelevant to the government regulations in one or more localities. Theseregulations may comprise data relevant to the allocation of licensed andunlicensed frequencies and the usage of those frequencies as well as themaximum allowable broadcast power for certain frequency ranges. Once theSDR factory component 45 has read the regulation data in 314, the SDRfactory component 45 in 315, determines if the operational parameters inthe SDR kernel 50 would violate any of the regulations provided by theregulations data 55. The SDR factory component 45 may first determinethe location where the SDR will be operating by prompting for theinformation or through an automatic process such as drawing inferencesusing GPS information. If it is determined in 315 that the SDR kernelspecifies an operational range which may violate pertinent regulationsoutlined by the regulation data 55, an error is raised in 316 and theprocess of constructing the SDR component is halted.

If it is determined that the SDR kernel 50 would not violate theregulations data 55, then the SDR factory component 45, in 317, reads aninterface harness 53 which, as previously disclosed, comprisescomponents for operatively connecting the simple interface described bythe SDR kernel 50 to more complicated interfaces for communicating withan SDR client 15 or an SDR hardware component 60. For example, if theSDR hardware component 60 is connected to a general-purpose computer bya USB connection, the interface harness 53 would comprise one or morecomponents for sending data over the USB connection to the particularSDR hardware component 60 being used. The SDR kernel 50 would provide abasic interface for sending data, but would have no description forsending data over USB or any specific commands for supporting aparticular SDR hardware component 60. When necessary, the interfacecomponents also translate control data and specifications databi-directionally between the format used by the SDR kernel 50 and theSDR hardware component 60.

In 318, the SDR factory component 45 constructs the SDR softwarecomponent 40. FIG. 4 shows a block diagram with more detail pertainingto the construction of an SDR software component 40 by an SDR factorycomponent 45. The SDR kernel 50 is converted to an SDR kernel component,which is a software description of the SDR kernel that is appropriatefor instructing a processor such as a general-purpose processor or fieldprogrammable gate array (“FPGA”) on how to execute (e.g., object code).If the SDR kernel 50 is provided in object code format suitable forinstructing the desired target host, then it may not be necessary toperform any explicit conversion. If the SDR kernel 50 is provided as thesource code of a programming language, then compilation and linking maybe used in parts of the conversion process. When provided in a dataformat (e.g., XML), the SDR kernel 50 can, for example, be parsed andconverted by a code generation component in the SDR factory component45.

If regulation data 55 is provided, the data is parsed and object code isgenerated for ensuring that control data sent from the SDR kernelcomponent to the SDR hardware component 60 will not violate regulations.The regulation component comprises this generated object code. The sameprocess applies to the specifications data containing the capabilitiesof the SDR hardware component 60. This specifications data is used togenerate the object code of which the specifications enforcementcomponent comprises. Once each individual component has been generated,they are appropriately linked together in order to function together asa system and form the SDR software component 40. The linking methodsused may comprise static linking and dynamic linking and the object codedefining the SDR software component may physically reside in multiplefiles or a single file.

We have disclosed aspects of the present invention directed toconstructing an SDR software component using various data such as theregulation data, SDR kernel, interface harness, and specifications fromthe SDR hardware component. We now turn our attention to aspects of thepresent invention directed to obtaining the regulation data and SDRkernel.

FIG. 5 is a block diagram illustrating an example of a system accordingto some aspects of the present invention. This system supports themodular construction of an SDR by providing a service through which thepreviously disclosed regulation data and SDR kernel may be obtained overthe Internet using the World Wide Web. The server system 530 comprisesvarious web pages 531, a server engine 532, a DRM engine 533, an SDRkernel database 534, a regulation database 535, a user database 536, alocality database 537, and a payment engine 538.

The server engine 532 receives HTTP requests to access web pages or webservice listeners identified by URLs and provides Web pages or SOAPresponses to the various client systems. Additionally, the server engine532 may receive requests for files to be transmitted over HTTP. If theserver engine approves the request, it sends the file to the clientsystem. The DRM engine 533 applies DRM policy to an SDR kernel and mayencrypt some or all of the contents of the SDR kernel before it is sentto a client system. The DRM policies may include: copy protection,setting time limitations on use of the SDR kernel, and binding the SDRkernel to a particular host.

The SDR kernel database 534 contains SDR kernels, each providing adescription of a component for implementing a radio standard, aspreviously disclosed. The SDR kernel database 534 additionally containspricing information for each SDR kernel, a unique identifier for eachSDR kernel, and an identifier for the radio standard that the SDR kerneldescribes. The regulation database 535 contains a description ofregulations applicable to each locality for which regulation data isavailable. The user database 536 contains a listing of registered users.For each registered user, the user database 536 additionally maycontain: authentication information (e.g., username and password),subscription information, and default locality preferences.

The locality database 537 contains a list of localities, as well asidentifiers for the radio standards that may be used in the locality.Additionally, the locality database 537 may have identifiers forallowing the definition of named geographical groupings of localitiesinto a tree-like hierarchy of any depth. For example, their may be agrouping for Earth, a sub-grouping for the Northern Hemisphere, anothersub-grouping for North America, another sub-grouping for the UnitedStates, another sub-grouping for Massachusetts, and finally the localityof Boston. This example is meant only to be illustrative and not serveto define the granularity of localities or define the scope of the namedgeographical groupings. The payment engine 538 provides the ability totake account information provided by users of the client system 510 andprocess payment transactions. These transactions may include receivingfunds from a credit card account, debit card, or any other suitableaccount.

The client system 510 comprises a web browser 511 for requesting anddisplaying web pages and may optionally comprise an SDR factorycomponent 45 and a DRM component 43. The client system 510 may also beconnected to an SDR hardware component 60 as previously disclosed. Theclient system 510 and the server system 530 communicate by exchanginginformation via a communications link 540 which may include transmissionover the internet.

One of ordinary skill in the art will appreciate that the techniquespresented above can be used in various environments other than the WorldWide Web. For example, rather than using a web browser 511 tocommunicate with the server system 530, another application (includingthe SDR factory component itself) could be used employing anotherprotocol for exchanging information. Files may be transmitted using avariety of protocols such as over email and file transfer protocol(“FTP”). Various communications links may also be used which do not usethe internet such as local area networks and point-to-point dialup. Boththe client and the server systems may comprise any combination ofhardware and software for providing the aforementioned functionality.

FIG. 6 is a flow diagram of an example routine for sending an SDR kernelto a client system. In 601, the server system 530 receives a requestfrom a client system 510 to connect to the server system 530 and acceptsthe request. In one embodiment, the client system 510 also sendsauthentication information indicating that the user of the system isregistered with the service provided by the server system 530. We notethat a user need not be a human operator, but may also be a softwareprogram or hardware device configured to communicate with the serversystem 530. In 602, the information is then checked against the userdatabase 536 to determine if the authentication information providedmatches a known user. If the information does not match, the user isdirected to register in 603. We note that in further acts of thisprocess, the server system 530 maintains an operatively statefulconnection to the web browser 511 on the client system 510 (i.e., doesnot confuse requests from one web browser 511 with those from another).When using HTTP (a stateless protocol), this may be accomplished throughthe use of browser cookies or data appended to the URLs of requests sentby the web browser 511.

In 604, the server system 530 generates a list of locality identifiersidentifying localities contained in the locality database 537. Herein,an identifier may be any data suitable for identifying a particular item(e.g., strings or numbers). It is understood that multiple identifierscan be used for a given item including one that is easy for humans toread and one that works well with World Wide Web standards (e.g., URLencoding). It is also understood that a list of geographical groupingsmay be generated and sent to the client system 510 rather than thelocalities themselves. Once the user has selected a particulargeographical grouping, the server system 530 may then return the nextlevel lower in the grouping tree until a set of leaves (i.e.,localities) are reached. The user of the client system 510 then selectsone of the locality identifiers and returns it to the server system 530where it is received in 605. The locality identifier received by theuser in 605 is kept in the user database 536 for later use.

Once a locality identifier is received, the server system can, in 606,query the locality database 537 for a list of radio standard identifiersidentifying radio standards that are used in the identified locality.This list can then be collected and sent to the client system 510. Theuser of the client system 510 then selects a desired radio standardidentifier and returns the selection to the server system 530, where itis received in 607. In 608, the server system generates a list of SDRkernel identifiers for SDR kernels which describe and SDR kernelcomponent for implementing the specified radio standard and sends thelist to the client system 510. The server system 530 may additionallysend publisher and pricing information for each of the SDR kernels alongwith the SDR kernel identifier. The publisher information may comprisedata such as: the name of the publisher, date of publication, version,and ratings.

Once the user has selected an SDR kernel identifier from the list, theserver system 530 receives the selection in 609. If it is determinedfrom the pricing information in the SDR kernel database 534 that theselected SDR kernel is free (i.e., of no monetary cost), the serversystem 530 sends the requested SDR kernel to the client system 510.Optionally, the regulation data for the identified locality receivedfrom the user in 605 may be sent along with the SDR kernel. Thisregulation data can be obtained by using the locality identifier storedin the user database 536 to query the regulation database 535 forpertinent regulation data. As previously disclosed, the SDR kernel andregulation data may be combined into a single file or kept separate. Theserver system 530 may use either approach when sending the SDR kerneland regulation data to the client system 510.

If it is determined in 610 that the selected SDR kernel is not free,then the server system 530 generates, from the payment informationstored in the SDR kernel database 534, a list of payment optionsavailable for the selected SDR kernel. Alternatively, the list ofpayment options may be the same for all SDR kernels which are not free.A variety of payment options are conceivable. One example of a paymentoption is the unlimited duration of usage of an SDR kernel for a fixedprice. Another example is the payment of a fixed price for a finiteduration of usage. It is also conceivable that the user might pay afixed monthly subscription fee for unlimited access to some or all ofthe SDR kernels. Once the user selects the desired payment option, theserver system 530 receives the selection in 613. The server system mayalso optionally receive account information from the user in 614indicating the account information for the account which should becharged for the transaction. Alternatively, this information can beprovided when the user registers in 603 and stored in the user database636. In this case, the account information received in 614 would be anindication that the data stored in the user database should be used.

In 615, the server system collects payment for use of the selected SDRkernel under the specified payment option using the payment engine 538.In 616, after receiving notification that the financial transaction wassuccessful, the server system 530 retrieves the specified SDR kernelfrom the SDR kernel database 534 and passes it, along with the detailsof the selected payment option, to the DRM engine 533. The DRM engine533 secures the contents of the SDR kernel using, for example,encryption technology and appends tamper-resistant DRM policies to theencrypted SDR kernel which reflect the terms of the service provided bythe server system 530 and the specific terms outlined by the selectedpayment option. Once the DRM engine 533 has finished applying DRM to theSDR kernel, the server system 530 returns the SDR kernel to the clientsystem 510. Optionally, the regulation data for the locality receivedfrom the user in 605 may be sent along with the SDR kernel. Thisregulation data can be obtained by using the locality data stored in theuser database 536 to query the regulation database 535 for pertinentregulation data. As previously disclosed, the SDR kernel and regulationdata may be combined into a single file or kept separate. The serversystem 530 may use either approach when sending the SDR kernel andregulation data to the client system 510.

Herein we have disclosed a variety of embodiments of an invention formodularly constructing an SDR. Methods for generating an SDR softwarecomponent have been disclosed, some supporting the separation of thedefinition of the core DSP and control elements of an SDR softwarecomponent (i.e., the SDR kernel component) which implement a particularradio standard from the host-dependent interface components. Instead,the SDR kernel component implements a simple interface that may becompletely host-neutral. These methods permit developers of SDR softwarecomponents to focus attention on implementing radio standards ratherthan wasting resources on building interfaces for a particularcommunication channel on a particular host. Additionally, with alldevelopers of SDR kernels components implementing a common, simpleinterface it becomes possible to more easily swap one SDR kernelcomponent with another while reusing the same interface components.

Further, we have disclosed a separation between the implementation ofthe core SDR software components (i.e., the SDR kernel component) on aparticular host and the description thereof (i.e., the SDR kernel). Thisdistinction is important because in some embodiments, an SDR kernel maybe expressed in a format that is independent of a particular hostwhereas the SDR kernel component comprises host-specific instructionsfor implementing a radio standard. This separation is even more usefulas it permits a host to effectively become a universal communicator,switching from one radio standard to another by using another SDRkernel. Such effortless modular construction of an SDR is furthersupported by an internet-based service we have disclosed, allowing usersto select from a plurality of SDR kernels in a variety of ways.

1. A method for modularly constructing a software defined radio (“SDR”)software component comprising acts of: (a) reading an SDR kernel, theSDR kernel comprising digital rights management (“DRM”) policies and adefinition of an SDR kernel component for implementing a radio standard,wherein a portion the SDR kernel is encrypted; (b) reading an interfaceharness, the interface harness comprising interfacecomponents foroperatively connecting the SDR kernel component to a plurality ofcommunication channels and devices, the devices including SDR hardwarecomponents; (c) constructing the SDR software component using the SDRkernel and the interface harness; (d) determining if the DRM policiesare satisfied; (e) terminating the construction of the SDR softwarecomponent if it is determined in act (d) that the DRM policies are notsatisfied; and (f) decrypting the encrypted portion of the SDR kernel ifit is determined in act (d) that the DRM policies are satisfied.
 2. Themethod of claim 1, wherein the SDR kernel further comprises data fordetermining if the SDR kernel has been modified from an intended state,further comprising acts of: (g) determining if the SDR kernel has beenmodified from the intended state; and (h) terminating the constructionof the SDR software component if it is determined in act (g) that theSDR kernel has been modified from the intended state.
 3. The method ofclaim 1, wherein the SDR kernel further comprises data for identifying apublisher of the SDR kernel, further comprising acts of: (g) determiningif the publisher of the SDR kernel is a trusted publisher; (h)requesting authorization to continue the construction of the SDRsoftware component if it is determined in act (g) that the publisher isnot a trusted publisher; and (i) terminating the construction of the SDRsoftware component if a negative response to the authorization requestof act (h) is received.
 4. The method of claim 1, wherein the SDR kernelfurther comprises data representing certifications of the SDR kernel bythird parties, further comprising acts of: (g) determining if the SDRkernel comprises a particular certification; (h) requestingauthorization to continue the construction of the SDR software componentif it is determined in act (g) that the particular certification is notpresent; and (i) terminating the construction of the SDR softwarecomponent if a negative response to the authorization request of act (h)is received.
 5. The method of claim 1, wherein the SDR kernel furthercomprises data describing minimum requirements for supporting the SDRkernel component described by said SDR kernel, further comprising actsof: (g) reading specifications data, the specifications data describingcapabilities of an SDR hardware component; (h) determining if thecapabilities of act (g) are sufficient to meet the described minimumrequirements; and (i) terminating the construction of the SDR softwarecomponent if it is determined in act (h) that the capabilities of act(g) are not sufficient to meet the described minimum requirements. 6.The method of claim 5, wherein the interface components translatespecifications data bi-directionally between a first format used by theSDR kernel and a second format used by at least one component of the SDRhardware components.
 7. The method of claim 1, further comprising an actof (g) reading specifications data, the specifications data describingcapabilities of an SDR hardware component; and wherein the constructionof the SDR software component additionally uses the specifications datato construct a specifications enforcement component for preventing theSDR software component from directing an SDR hardware component tooperate beyond the described capabilities of act (g).
 8. The method ofclaim 1, further comprising acts of: (g) reading regulation data, theregulation data comprising descriptions of regulations for a locality;(h) analyzing the SDR kernel to determine if the SDR software componentbeing constructed might violate the regulations of act (g); and (i)terminating the construction of the SDR software component if it isdetermined in act (h) that the SDR software component being constructedmight violate the regulations of act (g).
 9. The method of claim 1,further comprising an act of (g) reading regulation data, the regulationdata comprising descriptions of regulations for a locality; and whereinthe construction of the SDR software component additionally uses theregulation data to construct a regulation component for preventing theSDR software component from violating the described regulations.
 10. Themethod of claim 1, wherein the interface harness comprises an interfacecomponent for sending data over a Universal Serial Bus (“USB”) interfaceto at least one component of the SDR hardware components.
 11. Acomputer-readable medium storing computer-readable signals that defineinstructions which, as a result of being executed by a computer,configure the computer to perform a process for modularly constructing asoftware defined radio (“SDR”) software component, the processcomprising acts of: (A) reading an SDR kernel, the SDR kernel comprisingdigital rights management (“DRM”) policies and a definition of an SDRkernel component for implementing a radio standard, wherein a portionthe SDR kernel is encrypted; (B) reading interface components foroperatively connecting the SDR kernel component to a plurality ofcommunication channels and devices, the devices including SDR hardwarecomponents; (C) constructing the SDR software component using the SDRkernel and the interface components; (D) determining whether the DRMpolicies are satisfied; (E) when it is determined in act (D) that theDRM policies are not satisfied, terminating the construction of the SDRsoftware component; and (F) when it is determined in act (D) tat the DRMpolicies are satisfied, decrypting the encrypted portion of the SDRkernel.
 12. The computer-readable medium of claim 11, wherein the SDRkernel further comprises data for determining if the SDR kernel has beenmodified from an intended state, further comprising instructions forperforming acts of: (G) determining if the SDR kernel has been modifiedfrom the intended state; and (H) terminating the construction of the SDRsoftware component if it is determined in act (G) that the SDR kernelhas been modified from the intended state.
 13. The computer-readablemedium of claim 11, wherein the SDR kernel further comprises data foridentifying a publisher of the SDR kernel, further comprisinginstructions for performing acts of: (G) determining if the publisher ofthe SDR kernel is a trusted publisher; (H) requesting authorization tocontinue the construction of the SDR software component if it isdetermined in act (G) that the publisher is not a trusted publisher; and(I) terminating the construction of the SDR software component if anegative response to the authorization request of act (H) is received.14. The computer-readable medium of claim 11, wherein the SDR kernelfurther comprises data representing certifications of the SDR kernel bythird parties, further comprising instructions for performing acts of:(G) determining if the SDR kernel comprises a particular certification;(H) requesting authorization to continue the construction of the SDRsoftware component if it is determined in act (G) that the particularcertification is not present; and (I) terminating the construction ofthe SDR software component if a negative response to the authorizationrequest of act (H) is received.
 15. The computer-readable medium ofclaim 11, wherein the SDR kernel further comprises data describingminimum requirements for supporting the SDR kernel component describedby said SDR kernel, further comprising instructions for performing actsof: (G) reading specifications data, the specifications data describingcapabilities of an SDR hardware component; (H) determining if thecapabilities of act (G) are sufficient to meet the described minimumrequirements; and (I) terminating the construction of the SDR softwarecomponent if it is determined in act (H) that the capabilities of act(G) are not sufficient to meet the described minimum requirements. 16.The computer-readable medium of claim 15, wherein the interfacecomponents translate specifications data bi-directionally between afirst format used by the SDR kernel and a second format used by at leastone component of the SDR hardware components.
 17. The computer-readablemedium of claim 11, further comprising instructions for performing anact of (G) reading specifications data, the specifications datadescribing capabilities of an SDR hardware component; and wherein theconstruction of the SDR software component additionally uses thespecifications data to construct a specifications enforcement componentfor preventing the SDR software component from directing an SDR hardwarecomponent to operate beyond the described capabilities of act (G). 18.The computer-readable medium of claim 11, further comprisinginstructions for performing acts of: (G) reading regulation data, theregulation data comprising descriptions of regulations for a locality;(H) analyzing the SDR kernel to determine if the SDR software componentbeing constructed might violate the regulations of act (G); and (I)terminating the construction of the SDR software component if it isdetermined in act (H) that the SDR software component being constructedmight violate the regulations of act (G).
 19. The computer-readablemedium of claim 11, further comprising instructions for performing anact of (G) reading regulation data, the regulation data comprisingdescriptions of regulations for a locality; and wherein the constructionof the SDR software component additionally uses the regulation data toconstruct a regulation component for preventing the SDR softwarecomponent from violating the described regulations.
 20. Thecomputer-readable medium of claim 11, wherein at least one component ofthe interface components is configured to send data over a UniversalSerial Bus (“USB”) interface to at least one component of the SDRhardware components.